This article revisits the question of Alfred Russel Wallace's relationship to eugenics and explores the basis of Wallace's consistent rejection of attempts to label him a eugenicist. Whereas some scholars have identified an 'ambiguity' or 'tension' between Wallace's hereditarianism and his libertarianism and maintained - despite Wallace's statements to the contrary - that he was, in some senses, a eugenicist, this article argues that Wallace's oft-repeated claims he was not a eugenicist are fully justified. By exploring Wallace's relationship with Francis Galton using a hitherto neglected correspondence between the two concerning the establishment of a proposed laboratory, and Wallace's criticism of non-Darwinian evolutionary mechanisms in the writings of William Bateson and others, this article situates Wallace's opposition to eugenics in his broader ultra-Darwinian agenda. The article concludes by arguing that it is misleading to characterise Wallace as a eugenicist, and that doing so tends to obscure and confuse our understanding of his thought.

This article explores the early biogeographical debates that shaped the beginning of limnology, focusing on the differences of opinion concerning the origins of pelagic fauna between two pioneering scientists: Pietro Pavesi and François-Alphonse Forel. The study examines how Pavesi's hypothesis of a marine origin for pelagic fauna contrasts with Forel's theory of passive distribution, situating their arguments within a broader Darwinian framework. The first part of the paper provides a historical overview of Italian limnology, highlighting Pavesi's contributions and interpreting Forel's writings to underscore the significance of discovering pelagic fauna in conceptualizing lakes as microcosms. The second part compares Pavesi's and Forel's hypotheses, emphasizing their impact on the scientific understanding of freshwater ecosystems. The importance of this discovery, in both historical and scientific contexts, lies in recognizing the presence of plankton in lakes as a crucial element for the mature formulation of ecological concepts, such as the ecosystem.

There's something strange about Freud's Civilization and its Discontents (1930). Biologically, Freud was a Neo-Lamarckian, who believed in both the modification of organisms through need and the inheritance of acquired characteristics. However, in Civilization, Freud argued that because human nature is immutable, society has dim odds of improving substantially. Lamarckians, of course, rejected that any species-nature is immutable, as species can always be transformed via the inheritance of acquired characteristics. In fact, many of Freud's Viennese contemporaries-such as Wilhelm Reich, Julius Tandler, and Paul Kammerer-took their Lamarckism to license precisely the sorts of radical social projects Freud deemed impossible. Thus the Freud of Civilization helped himself to a rigid view of human nature which, given his associated biological views, he seemingly ought to have rejected. In this paper, I explain this apparent inconsistency, and suggest Freud resolved it in the following way: Freud was not merely a Lamarckian, but also a strong and peculiar kind of recapitulationist, who believed stages of psychological development both recapitulate phylogeny, and "remain with us" throughout both individual lives and future species-history. I suggest Freud's recapitulationism supposed a certain inertia: what occurred in phylogenetic history cannot un-occur, and therefore there are aspects of our nature which we cannot un-acquire. In this way, Freud reached a rigid conception of human nature despite his Lamarckism.

Interest in the study of domesticated plants increased near the end of the 18th century, mainly because of their economic potential. In the 19th century, there was a new focus on the historical understanding of species, their origin, changes in their distribution, and their evolutionary history. Charles Darwin developed an extended interpretation of species domestication, considering variations, reproduction, inheritance, and modification as standard processes between wild and domesticated organisms. In this context, one relatively neglected aspect was the geographical distribution of domesticated species. Alphonse de Candolle addressed and developed in detail the question of the geographical origin of cultivated plants. Since 1836 Alphonse de Candolle had been studying the topic and obtained evidence that contributed to understanding aspects such as the center of origin, dispersion, competition, selection, and time of domestication. Although Darwin himself admitted that Géographie botanique raisonnée (de Candolle, Alphonse,de. Géographie botanique raisonnée; ou, exposition des faits principaux et des lois concernant la distribution géographique des plantes de l'epoque actuelle, 2ème tome. Paris: Masson.) was of great help to him in the development of his evolutionary theory, the importance of de Candolle's contribution is seldom recognized. Our purpose is to detail the dialogue between Alphonse de Candolle and Darwin on the geography of domesticated plants, to understand some of the most critical discussions that contributed to the reinterpretation of domestication under the Darwinian proposal of modified descent.

Tree diagrams are the prevailing form of visualization in biological classification and phylogenetics. Already during the time of the so-called Systematist Wars from the mid-1960s until the 1980s most journal articles and textbooks published by systematists contained tree diagrams. Although this episode of systematics is well studied by historians and philosophers of biology, most analyses prioritize scientific theories over practices and tend to emphasize conflicting theoretical assumptions. In this article, I offer an alternative perspective by viewing the conflict through the lens of representational practices with a case study on tree diagrams that were used by numerical taxonomists (phenograms) and cladists (cladograms). I argue that the current state of molecular phylogenetics should not be interpreted as the result of a competition of views within systematics. Instead, molecular phylogenetics arose independently of systematics and elements of cladistics and phenetics were integrated into the framework of molecular phylogenetics, facilitated by the compatibility of phenetic and cladistic practices with the quantitative approach of molecular phylogenetics. My study suggests that this episode of scientific change is more complex than common narratives of battles and winners or conflicts and compromises. Today, cladograms are still used and interpreted as specific types of molecular phylogenetic trees. While phenograms and cladograms represented different forms of knowledge during the time of the Systematist Wars, today they are both used to represent evolutionary relationships. This indicates that diagrams are versatile elements of scientific practice that can change their meaning, depending on the context of use within theoretical frameworks.

This paper offers an historical introduction to Pere Alberch's evolutionary thought and his contributions to Evo-Devo, based on his unique approach to experimental teratology. We will take as our point of reference the teratogenic experiments developed by Alberch and Emily A. Gale during the 1980s, aimed at producing monstrous variants of frogs and salamanders. We will analyze his interpretation of the results of these experiments within the framework of the emergence of evolutionary developmental biology (or "Evo-Devo"). The aim is understand how Alberch interpreted teratological anomalies as highly revealing objects of study for understanding the development of organic form, not only in an ontogenetic sense-throughout embryonic development-but also phylogenetically-throughout the evolution of species. Alberch's interpretation of monsters reflects the influence of a long tradition of non-Darwinian evolutionary thought, which began in the nineteenth century and was continued in the twentieth century by people such as Richard Goldschmidt, Conrad H. Waddington, and Stephen Jay Gould. They all proposed various non-gradualist models of evolution, in which embryonic development played a central role. Following this tradition, Alberch argued that, in order to attain a correct understanding of the role of embryological development in evolution, it was necessary to renounce the gradualist paradigm associated with the Darwinian interpretation of evolution, which understood nature as a continuum. According to Alberch, the study of monstrous abnormalities was of great value in understanding how certain epigenetic restrictions in development could give rise to discontinuities and directionality in morphological transformations throughout evolution.

This study investigates nineteenth century natural history practices through the lens of the Actor-Network Theory, which posits that scientific practice is shaped by an intricate network of interactions between human and non-human actors. At the core of this research is the analysis of correspondence between Charles Darwin and his collaborators during the Cirripedia Project, which unveils a complex landscape of negotiations with illustrators, funders, specimen owners, and translators, among other stakeholders and interested parties. The study goes beyond the final outcomes of scientific research, delving into behind-the-scenes interactions, and hidden constructions, shedding light on the complex dynamics and actors that conventional scientific narratives often overlook. In general, this approach provides a detailed and insightful view of the underlying processes of nineteenth-century scientific practice, underscoring the importance of epistolary correspondence as a central element in producing scientific knowledge at the time, and in particular it reveals to us how much Darwin was himself involved in the production of his famous work on barnacles. By emphasizing the intricacies of research, this study enriches our understanding of Darwin's work as well as natural history practices in the 19th century, highlighting the complexity and diversity of actors and agents involved in shaping scientific knowledge.

The importance of naturalization-the establishment of species introduced into foreign places-to the early development of Darwin's theory of evolution deserves historical attention. Introduced and invasive European species presented Darwin with interpretive challenges during his service as naturalist on the HMS Beagle. Species naturalization and invasive species strained the geologist Charles Lyell's creationist view of the organic world, a view which Darwin adopted during the voyage of the Beagle but came to question afterward. I suggest that these phenomena primed Darwin to question the "stability of species." I then examine the role of introduced and invasive species in Darwin's early theorizing and negotiation with Lyell's ideas, recorded in his post-voyage "transmutation notebooks." Therein, the subject was an inflection point in his contention with Lyell's views and moreover, his theorizing on invasive species occasioned some of his earliest inklings of natural selection. Finally, I examine how naturalization was crucial to Lyell's own eventual conversion to evolutionism. I conclude with brief reflections on the implications of this narrative for our understanding of Darwin's reasoning, his intellectual relationship to Lyell, and the historical context that shaped his theory.

William Lawrence Tower's work on the evolution of the Colorado Potato Beetle (Leptinotarsa decemlineata), documenting the environmental induction of mutation and speciation, made him a leading figure in experimental genetics during the first decade of the 20th century. His research program served as a model for other experimental evolution studies seeking to demonstrate the environmental modification of inheritance. Tower enjoyed the support of influential figures in the field, despite well-known problems that plagued Tower's earlier academic career. The validity of his genetic work, and other findings reported by Tower, were later challenged. The Tower affair illustrates how questionable and possibly fraudulent scientific practices can be tolerated to explore certain experimental directions and theoretical frameworks, particularly at the frontier of expanding disciplines. When needed, those explorations can be forestalled or extinguished by exploiting conspicuous vulnerabilities of rogue practitioners. In Tower's case, both unrefuted allegations of scientific misconduct and personal problems dissolved his institutional support, leading to a swift ouster from academic science. Tower's downfall discredited soft inheritance and neo-Lamarckian conceptions in the field of experimental genetics, facilitating the discipline's embrace of a hard inheritance model that featured a hereditary material resistant to environmental modification.

While model organisms have had many historians, this article places studies of humans, and particularly our development, in the politics of species choice. Human embryos, investigated directly rather than via animal surrogates, have gone through cycles of attention and neglect. In the past 60 years they moved from the sidelines to center stage. Research was resuscitated in anatomy, launched in reproductive biomedicine, molecular genetics, and stem-cell science, and made attractive in developmental biology. I explain this surge of interest in terms of rivalry with models and reliance on them. The greater involvement of medicine in human reproduction, especially through in vitro fertilization, gave access to fresh sources of material that fed critiques of extrapolation from mice and met demands for clinical relevance or "translation." Yet much of the revival depended on models. Supply infrastructures and digital standards, including biobanks and virtual atlases, emulated community resources for model organisms. Novel culture, imaging, molecular, and postgenomic methods were perfected on less precious samples. Toing and froing from the mouse affirmed the necessity of the exemplary mammal and its insufficiency justified inquiries into humans. Another kind of model-organoids and embryo-like structures derived from stem cells-enabled experiments that encouraged the organization of a new field, human developmental biology. Research on humans has competed with and counted on models.

Ernst Brücke's 1861 essay Die Elementarorganismen has often been cited as a watershed in the history of physiology as well as in the history of cell theory. In its time it was widely read as a reform of animal cell theory, shifting the concept of the cell away from Schleiden and Schwann's original cell schema of a membranous vesicle with a nucleus, and towards the protoplasm theory that had developed in botany, centered on the cell's living contents. It was also notorious for its arguments against the necessity of both the nucleus and the cell membrane. An English translation of "The Elementary Organisms" is presented for the first time in this journal issue, with annotations and illustrations, https://doi.org/10.1007/s10739-024-09773-9 . Brücke's essay was not only an intervention into cell theory: historians can read it as a continuation of debates on the nature of the organism and theories of organization, and as an epistemological meditation on the microscope. In addition, although Brücke was known as a founder of the Berlin school of organic physics, "The Elementary Organisms" shows how he combined an avant-garde physicalist physiology with a much older tradition of comparative anatomy and physiology. The following introductory essay will provide a scientific biography of Ernst Brücke up to 1863, with background on debates on biological organization, cell theory, and muscle histology.

In 1861 the physiologist Ernst Brücke (1819-1892) published "The Elementary Organisms," calling for a major reform of the definition of the animal cell. An English translation of Brücke's essay is presented here for the first time. In this translation the numbered footnotes 1-9 are Brücke's own; alphabetical endnotes A-HH are my own annotations, with additional references to works cited by Brücke. Figures referenced by Brücke but not included in his original essay are also provided. I have also presented an introductory essay to my translation that provides background on Brücke and his arguments: "The Schema and Organization of the Cell," https://doi.org/10.1007/s10739-024-09774-8 , in this same issue of the Journal of the History of Biology.

During the 1890s, animal development became associated with glandular activity, with profound implications for pediatric nosology and treatment. The significance of this endocrinological turn of developmental physiology and pathophysiology in part hinges on an often-overlooked continuity with ubiquitous early modern medical thought concerning semen as a recrementitious (reabsorbed) nutrient or stimulant. Mid-19th-century interests in adult sexual physiology were increasingly nerve-centered and antihumoral. Scattered empirical, particularly veterinarian, interests in gonadal developmental functions failed to moderate these explanatory trends. While Brown-Séquard's rejuvenation experiments still offered no clear starting point for a developmental endocrinology, in 1892 Gaston Variot and Paul Bezançon more explicitly deduced a testicular developmental endocrinological function from various observations on testicular ectopy and a local form of animal "demi-castration." Ensuing interest in the thyroid, the thymus and in the testicles led to various working conceptions of their respective and putatively reciprocal developmental properties, including the idea of a thyroid-testis axis. From 1896, the pubertal affliction of chlorosis became the subject of multiple opotherapeutic approaches, providing an experimental basis for theories of ovarian internal secretion. Polyglandular therapy, piloted for divergent developmental conditions, remained routine until the 1930s despite the biological inefficacy of many endocrine products.

This paper revisits Fleeming Jenkin's anonymous review of Charles Darwin's Origin of Species, published in the North British Review in June 1867. This review is usually revered for its impact on Darwin's theory of descent with modification. Its classical interpretation states that Jenkin, a Professor of Engineering at the University of Edinburgh, made a compelling case against natural selection based on the fact of "blending inheritance" and the "swamping" of advantageous variations. Those themes, however, are strikingly absent from Jenkin's text. They were later read into Jenkin's text by scholars trying to explain how Darwinian selection was reconciled with Mendelian genes and the birth of the Modern Synthesis. While many scholars have tried to measure Jenkin's effect on Darwin, the value of the 1867 review remains unclear. This paper re-examines its content and concludes that Jenkin's "able review" was in fact written by an engineer whose competencies in biology were very low. Focusing on the figure of the shipwrecked white sailor isolated on an island inhabited by Black people, this paper also underlines the racial assumptions behind Jenkin's review. "Blending inheritance" is thus a theme linked to theoretical reworkings on the question of race and skin colors, taking its root in Galton's typology of heredity. Darwin was probably mostly unimpressed by Jenkin's review. The problems raised by the review were not so much "blending inheritance" and "swamping" but a conundrum of problems related to the effects of intercrossing on variation and reversion.